1. Field of the Invention
The present invention relates to a lever-operated wheelchair, which can be moved forward or maneuvered as one pleases by simply operating a lever or levers. More specifically, this invention relates to a wheelchair that is moved forward by the power generated by a reciprocating movement of an operation lever, and backward by the operation of push rims.
2. Prior Art
Most of the conventional hand-operated wheelchairs are operated with push rims, i.e., operation rings that are attached to the rims of the wheels. In order to make it possible to operate a wheelchair with one hand, the applicant of this invention proposed a lever-operated wheelchair for one-hand operation in the Japanese Patent Application No. 190091/1981 (Japanese Patent Publication No. 58808/1985). This wheelchair has an operation lever, which can be pushed forward or pulled backward from the neutral position to rotate the wheels forward or backward correspondingly. This wheelchair was granted a patent (Pat. No. 1330760) and has been widely used for one-hand operation applications. While this wheelchair moves forward when the operation lever is pushed forward, another type of wheelchair employing a pulling motion, which is thought to produce stronger power than a pushing motion, for the forward movement was proposed in the Japanese Patent Application No. 274210/1994 (Japanese Patent Laid-Open No. 103465/1996). This latter wheelchair is designed to use both hands. Apart from wheelchairs, a tricycle that is driven forward when a linearly reciprocal lever is pushed or pulled was published on pp. 78-79 of the Feb. 17, 1997, issue of the Nikkei Mechanical Magazine.
The two types of lever-operated wheelchairs for one-hand operation cited above are moved forward only when the lever is pushed (in the case of the former wheelchair) or only when the lever is pulled (in the case of the latter wheelchair). The tricycle, on the other hand, has a mechanism that uses both a push and a pull of the lever to move the tricycle forward, but this mechanism, comprising two roller clutches and five bearing gears, is very complicated and bulky, and is therefore difficult to be used in a wheelchair.